I host my name server's myself. If Mozilla is really doing this, they're misguided. All this does is make it impossible to serve requests from nearest webserver. You are getting the ip address anyways, so why do this? This means if I get someone from netherlands I'd have to redirect their requests from www.example.com to nl.example.com or buy an ipv4 block, set up anycast and then serve from the closest ipaddress/server. The end result is same. I'll always get the end user's ip address unless they use a VPN or something.
This is a stupid decision by Mozilla. Too bad Firefox users when visiting websites making their own CDN's without anycast/country level redirects will see much slower sites.